2017-028 ABSTRACT Ventilation Perfusion Protector Embodiments of the present invention provide an ancillary device for the cardiopulmonary bypass and a ventilator. In particular, invention relates to a device 5 comprising a first sensor, a second sensor and a controller configured to receive signals from said sensors, and an output means producing an alarm when the outputs from the first and the second sensors are less than a threshold value for more than a threshold amount of time. 19